> i can't find anything about it googling for "s1457 4257".
That's because "1457 4257" is that particular unit's Job Identification Number, and the "S" at the beginning indicates that it's a production unit rather than a test or sample. There's no part identifier on it.
There's a hole in it, you just can't see it from that angle. Bottom port mics, where the hole is in the underside of the package and there's a matching hole in the PCB to allow sound in, are more common (and typically perform better) than top port mics, where the hole would be visible from the top side of the package. Both kinds do exist though.
interesting. i lack the competence to solder around on a smartphone pcb. would it be sufficient to just poke the hole with a needle or drop a small amount of super glue i/onto it?
Probably. There's a membrane past the hole that you can destroy and I doubt the mic could function well enough to worry about if you punctured it.
But I usually just crush the whole mic package with pliers when I need to remove one. They pry off the board pretty easily in my experience.
https://www.indiatoday.in/technology/features/story/when-edw...